Problem $2\mathrm{.}29$: Calculate the coefficient of isothermal compressibility of isobutane as saturated liquid and saturated vapor at $30C,$ Psat $=4\mathrm{.}05$ bar, using the SRK equation. Report the result in bar ${?}^{-1}.$

Hint: Recall from calculus that

$(\frac{\text{d}\text{e}\text{l}\text{V}}{\text{d}\text{e}\text{l}\text{P}}{)}_T=\frac{1}{(\frac{\text{d}\text{e}\text{l}\text{P}}{\text{d}\text{e}\text{l}\text{V}}{)}_T}$